Electricity generated by a power plant is transmitted across a high-voltage transmission network to distribution networks for distribution to local businesses and residences. The high-voltage power is reduced by a substation for transmission across a distribution network that includes a series of distribution lines and distribution transformers. Whether the distribution lines are carried overhead by power poles, or buried underground, the voltage of the transmitted electricity on the distribution lines is typically reduced by a distribution transformer at or near the business or residence. In a residential neighborhood, a single distribution transformer typically serves four to eight residences, with all electricity consumed by the four to eight residences being conducted through the same power distribution transformer.
The utility company supplying the electricity through the distribution network chooses an appropriately-sized distribution transformer based on typical power consumption of its customers in a particular area. If the distribution transformer is undersized in terms of its capacity to provide power to its connected residences and associated power-consuming devices, the transformer eventually fails, resulting in a temporary loss of power to those connected to the transformer, and eventual replacement of the existing transformer with a larger-capacity transformer.
This scenario is becoming more and more common with the proliferation of electric vehicles. While the use of commercial charging stations is becoming more common, owners of electric vehicles more typically charge their electric vehicles during the evening hours using charging stations located at their homes. Charging an electric vehicle consumes a relatively high amount of electricity in a relatively short period of time. Although the actual power consumed depends on the particular vehicle and the extent of charging required, some known electric vehicles may consume up to three times the electricity used by a typical residential household.
Regions having a high adoption rate of electric vehicles experience a “clustering” problem when multiple electric vehicles charge from a single distribution transformer. As more and more electric vehicles are added, more and more distribution transformers are operated beyond their rated capacity, and eventually must be replaced.
One solution to this clustering problem is to simply replace all existing distribution transformers with larger-capacity transformers in those cities, towns, or neighborhoods where the adoption rate of electric vehicles is known to be particularly high. Obviously though, this solution would be exceedingly costly and inefficient to implement.
Another solution is to replace existing distribution transformers with “smart” distribution transformers. One such solution is described in U.S. Pat. No. 8,024,077 to Torre et al. (“Tone”). Torre discloses a smart transformer that utilizes a balancing algorithm to determine a rating of the transformer, then either brings on additional generation if available, or sends an alarm to the utility company along with a busy signal to a customer, requesting that electrical loads be reduced. However, such a solution fails to provide an autonomous system that allows equitable sharing of available power resources amongst those loads sharing the distribution transformer.